[automation] Update EPR version to v1.23.1 (#1695)

Author: elasticmachine

internal/stack/resources.go

@@ -43,7 +43,7 @@ const (
 	PackageRegistryConfigFile = "package-registry.yml"
 
 	// PackageRegistryBaseImage is the base Docker image of the Elastic Package Registry.
-	PackageRegistryBaseImage = "docker.elastic.co/package-registry/package-registry:v1.23.0"
+	PackageRegistryBaseImage = "docker.elastic.co/package-registry/package-registry:v1.23.1"
 
 	// ElasticAgentEnvFile is the elastic agent environment variables file.
 	ElasticAgentEnvFile = "elastic-agent.env"